Film for medicine packaging and method of preparing the same

ABSTRACT

The present invention discloses a film for a medicine packaging and a method of preparing the same. The film for the medicine packaging includes a polymer film layer, a graphene composite layer and a light-curable adhesive, wherein the polymer film layer is bonded with a graphene composite layer by a light-curable adhesive, the graphene composite layer includes multiple graphene layers bonded by the light-curable adhesive; and the light-curable adhesive includes a hyperbranched cationic mussel-imitated polymer including a multi-hydroxylbenzoylbenzamide ene amide monomer, a cationic monomer and a photo-responsive monomer. The present invention provides strong adhesion with reduced adhesive layer, allowing greatly increasing the number of the graphene layers in the graphene composite layer without obvious increase in the total thickness and mass. This can meet the requirements of the medicine packaging material, as it obviously lowers the film&#39;s permeation to water vapor and oxygen and significantly enhances the tensile strength.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit under 35 U.S.C. § 119 of ChineseApplication No. 201811020242.1, filed Sep. 3, 2018, which is herebyincorporated in its entirety.

FIELD OF THE INVENTION

The present invention relates to the field of packaging material, andmore particularly to a film for a medicine packaging and a method ofpreparing the same.

BACKGROUND OF THE INVENTION

As the main packaging material for the pharmaceuticals, polymer filmpackaging material has become increasingly important in daily life.However, affected by the production processes and physicochemicalcharacteristics of the plastic films, the barrier properties of theplastic films to oxygen, water vapor, liquid substances and other lowmolecular weight substances are difficult to meet the requirements ofmost medicine packaging. The penetration of small molecular gases suchas oxygen and water vapor into the packaging materials may cause theoxidation deterioration of the active ingredients in the drug, whichgives rise to some phenomena like the proliferation of microorganisms,significantly shortening the shelf life of the drug. Therefore, theimprovement of the barrier properties of plastic films to smallmolecular gases such as oxygen and water vapor and the possession ofantibacterial properties are of great importance to improve the qualityof the plastic films.

Graphene is a two-dimensional carbon nanomaterial, wherein each carbonatom connects with the other three carbon atoms to form covalent bondsby means of sp² hybridization, and then arrange into a honeycombhexagonal lattice. The remaining single electron 2P orbital of eachcarbon atom coincides with each other to form a delocalized conjugated πbond. The six-membered ring of the graphene has a pore size of only 0.15nm which is smaller than that of helium, and has natural gas barrierproperties. Meanwhile, the transmittance of the single-layered grapheneto visible light reaches up to 97%, allowing that the single-layeredgraphene can be used to easily produce film materials with excellentlight transparency under suitable process conditions. Also, thesingle-layered graphene has a thickness of only 0.34 nm and a widthranging from a few microns to tens of centimeters. The aforementionedcharacteristics and properties make graphene to be an ideal nanometerbarrier material.

At present, one of the methods of using graphene to prepare a polymerfilm is to adopt an adhesive to bond the graphene film material and thepolymer film together. Nonetheless, due to the small contact area and afew reaction sites between the existing adhesive and the graphene, thesafety and bonding strength of the film are poor. Meanwhile, unevencoating of the adhesive causes not only a poor boding strength betweenthe graphene film and the polymer film, but also the difference in thethickness throughout the graphene film, resulting in differences inbarrier properties of the medicine packaging, which is difficult to meetthe requirements of the medicine packaging. Moreover, the existingpreparation process for the polymer film is highly polluting and has acomplicated post-treatment process, which cause a high production cost.

BRIEF SUMMARY OF THE INVENTION

The present invention aims to provide a film for a medicine packagingand a method of preparing the same, so as to solve the problems that thebarrier property of the existing medicine packaging is poor, and thepreparation process thereof is highly polluting and has a complicatedpost-treatment process, which cause a high production cost.

The present invention is realized by the following technical solutions:

A film for a medicine packaging, comprising a polymer film layer,wherein the polymer film layer is bonded with a graphene composite layerby a light-curable adhesive, the graphene composite layer comprises aplurality of graphene layers, and two adjacent graphene layers of theplurality of the graphene layers are bonded by the light-curableadhesive; and the light-curable adhesive comprises a hyperbranchedcationic mussel-imitated polymer, and the hyperbranched cationicmussel-imitated polymer comprises a multi-hydroxylbenzoylbenzamide eneamide monomer, a cationic monomer and a photo-responsive monomer.

In the prior art, Chinese patent having a patent number of CN103381934Adiscloses a food packing bag. The food packing bag comprises a grapheneantibacterial layer and a plastic layer, wherein the edges of thegraphene antibacterial layer and the plastic layer are bonded togetherby a flexible white emulsion. However, the adhesive used in the existingfilm material has a few reaction sites to chemically react with thegraphene, which causes a poor bonding strength between the polymer filmlayer and the graphene layer, making the graphene layer of the bondedpackaging film tend to peel off from the polymer film layer. Althoughthe amount of the adhesive can be increased to obtain a better bondingeffect, the thickness of the adhesive layer is increased, which lowerthe thickness of the graphene layer so that the total thickness isconstant, resulting in a poor barrier property of the graphene layerthat is difficult to meet the requirements of the medicine packaging.

To solve the aforementioned problems, the present invention provides afilm for the medicine packaging. The film for the medicine packagingcomprises a polymer film layer, wherein the polymer film layer can usethe common polymer film for medicine packaging such as polypropylene(PP), polyethylene (PE), polyethylene terephthalate (PET), polyvinylchloride (PVC), polybutylene terephthalate (PBT) and the like. Thepolymer film layer is bonded with a graphene composite layer by alight-curable adhesive, namely a first adhesive layer, and the graphenecomposite layer comprises a plurality of graphene layers. Two adjacentgraphene layers of the plurality of the graphene layers are bonded by asecond adhesive layer formed by the light-curable adhesive. That is tosay that the second adhesive layer and the graphene layer arealternatively coated on the polymer film layer. Preferably, the numberof layers of the plurality of the graphene layers in the graphenecomposite layer is 1-30.

The light-curable adhesive used in such technical solution comprises ahyperbranched cationic mussel-imitated polymer. The hyperbranchedcationic mussel-imitated polymer comprises amulti-hydroxylbenzoylbenzamide ene amide monomer and a cationic monomer.Preferably, the multi-hydroxylbenzoylbenzamide ene amide monomer isN-(2-acrylamidoethyl)-4-(2,3,4-trihydroxybenzoyl)benzamide,N-(2-acrylamidoethyl)-4-(3,4-dihydroxybenzoyl)benzamide orN-(2-acrylamidoethyl)-3-(2,3,4-trihydroxybenzoyl)benzamide. The cationicmonomer is any one of N-(2-aminoethyl)acrylamide hydrochloride,N-(2-aminoethyl)methacrylamide hydrochloride,N-(3-aminopropyl)acrylamide hydrochloride,N-(3-aminopropyl)methacrylamide hydrochloride,N-(4-aminobutyl)acrylamide hydrochloride, N-(4-aminobutyl)methacrylamidehydrochloride, N-(6-aminohexyl)acrylamide hydrochloride,N-(6-aminohexyl)methacrylamide hydrochloride or(2-aminoethyl)methacrylate hydrochloride.

The multi-hydroxylbenzoylbenzamide ene amide monomer has a large amountof free catechol groups. In the presence of the cationic end groups, thebonding force of the catechol groups to the polymer film layer can beenhanced by synergistic action between the catechol groups and thecationic end groups. Besides, a large amount of free catechol groups andthe cationic end groups allows the hyperbranched cationicmussel-imitated polymer to have good adhesions to various kinds ofpolymer film layers through a series of intermolecular forces withdifferent strength such as van der Waals force, hydrogen bonding, theinteracting force between cationic and pi and the like. Thus, thebonding strength between the polymer film layer and the adhesiveprepared by the hyperbranched cationic mussel-imitated polymercomprising the multi-hydroxylbenzoylbenzamide ene amide monomer and thecationic monomer can be enhanced significantly.

The hyperbranched cationic mussel-imitated polymer further comprises aphoto-responsive monomer. Preferably, the photo-responsive monomer canbe any one ofN-(2-acrylamidoethyl)-4-azido-2,3,5,6-tetrafluorobenzamide,N-(2-acrylamidoethyl)-4-azido-2,3,5-trifluorobenzamide,N-(2-acrylamidoethyl)-4-azido-2,5-difluorobenzamide orN-(2-acrylamidoethyl)-4-azidobenzamide.

Apart from the intermolecular force between the photo-responsive monomerand graphene molecule, the photo-responsive monomer can generate abenzene ring radical under action of light. The benzene ring radical mayattack the C—H bond on the graphene molecule and chemically react toform the covalent bond, which the latter greatly improve the bondingstrength between the polymer and the graphene molecule.

In sum, the light-curable adhesive prepared by the hyperbranchedcationic mussel-imitated polymer significantly enhances the bondingstrength between the adhesive and the polymer film layer, as well as thebonding strength between the adhesive and the graphene layers. Thestrong adhesion can be obtained with a less amount of adhesive so thatthe total thickness of the adhesive layers which include the firstadhesive layer and the second adhesive layers is reduced, allowing thenumber of layers of the graphene layers in the graphene composite layerto increase greatly without the change in the total thickness andobvious increase in the total mass, which not only meets therequirements of the medicine packaging material, but also obviouslylowers the water vapor transmission and oxygen transmission, andsignificantly enhances the tensile strength.

As a preferred structure of the hyperbranched cationic mussel-imitatedpolymer provided in the present invention, the hyperbranched cationicmussel-imitated polymer has a structure of formula (I):

wherein x is 1-10, y is 20-80, z is 30-80, w is 5-20, u is 20-80, K is1-5, n is 10-50, and m is 5-30;

wherein R₁ is a chemical group having a structure of formula (II):

wherein R₃, R₄, R₅ or R₆ is individually selected from the groupconsisting of hydrogen and halogen; and

wherein R₂ is a chemical group selected from the group consisting of

As shown in formula (II), the groups of R₃, R₄, R₅ and R₆ in R₁ canpartially or totally be halogen. Preferably, the groups of R₃, R₄, R₅and R₆ can partially or totally be fluorine. Under light condition, thenumber of the covalent bonds formed between fluorine and graphene istunable, so that the binding strength between the hyperbranched polymerand graphene is changeable according to the light intensity, whichallows the adhesive strength of the adhesive to be adjusted dependingupon the specific demands, and makes the adhesive more suitable for thegraphene film packaging material. Preferably, the polymerization degreeof the hyperbranched polymer is from 100 to 400. Further preferably, Kis 1-3, n is 20-30, and m is 10-20.

Compared with the traditional small molecule adhesive and the commonpolymer adhesive, the hyperbranched cationic mussel-imitated polymerdisclosed in the present invention has excellent mussel-imitatednon-selective adhesive property, good biocompatibility and adhesivestrength adjustability.

Furthermore, in formula (II), R₃, R₄, R₅ or R₆ is individually selectedfrom the group consisting of hydrogen and fluorine.

As a preferred structure of R₁, R₁ is selected from the group consistingof

Furthermore, a thickness of the graphene composite layer is 10-200 nm.Preferably, the graphene composite layer having a thickness of 30-70 nmallows the film for the medicine packaging to have good lighttransmittance, gas permeability and quality.

The present invention further provides a method of preparing theaforementioned film for medicine packaging, which comprises followingsteps:

(A) using the reversible addition fragmentation chain transferpolymerization method to prepare the hyperbranched cationicmussel-imitated polymer, and formulating the prepared hyperbranchedcationic mussel-imitated polymer into an aqueous solution of thelight-curable adhesive;

(B) preparing a reduced graphene oxide solution;

(C) spraying the aqueous solution of the light-curable adhesive preparedin the step (A) on the polymer film layer to form a first adhesivelayer, then spraying the reduced graphene oxide solution prepared in thestep (B) on the first adhesive layer to form one of the plurality of thegraphene layers, and curing the first adhesive layer under a lightcondition;

(D) spraying the aqueous solution of the light-curable adhesive preparedin the step (A) on the one of the plurality of the graphene layersprepared in the step (C) to form a second adhesive layer, then sprayingthe reduced graphene oxide solution prepared in the step (B) on thesecond adhesive layer to form another one of the plurality of thegraphene layers, and then curing the second adhesive layer under thelight condition; and

(E) repeating the step (D) until a desired number of layers of theplurality of the graphene layers in the graphene composite layer beingachieved.

In the step (A), the reversible addition fragmentation chain transferpolymerization method (RAFT) is used to prepare the hyperbranchedcationic mussel-imitated polymer, which the latter comprises amulti-hydroxylbenzoylbenzamide ene amide monomer, a cationic monomer anda photo-responsive monomer. Later, the prepared hyperbranched cationicmussel-imitated polymer is formulated into an aqueous solution of thelight-curable adhesive having a concentration of 0.5-5.0 mg/mL forsubsequent use.

In the step (B), the graphene oxide can either be commerciallyavailable, or be prepared by Hummers method. Then the graphene oxide maybe reduced by a reducing agent to obtain a dispersive and stable reducedgraphene oxide solution. Preferably, the reducing agent can be any oneof sodium ascorbate, hydroiodic acid, hydrazine hydrate or sodiumborohydride.

In the step (C), first, the aqueous solution of the light-curableadhesive is evenly sprayed on the polymer film layer to form the firstadhesive layer. Then the reduced graphene oxide solution is sprayed onthe first adhesive layer to form one of the plurality of graphenelayers. Preferably, the concentration of the reduced graphene oxidesolution is 0.01-5 mg/mL. Later, the film is subjected to the light tocure the adhesive. Prior to carrying out the step (C), the surface ofthe polymer film can be cleaned with water to remove contaminantsthereon, improving the adhesion of the surface of polymer film.

In the prior art, before the adhesive is sprayed on the polymer film,the polymer film is typically subjected to a corona treatment. In thepresent invention, the multi-hydroxylbenzoylbenzamide ene amide monomercomprises a large amount of catechol groups which can form variousintermolecular forces such as hydrogen bonding, van der Waals force, theinteracting force between cationic and pi and the like with the surfaceof the polymer film, thereby bonding firmly with the surface of thepolymer film. Therefore, the aqueous solution of the light-curableadhesive sprayed on the surface of the polymer film layer can bind withthe polymer film layer firmly even without the corona treatment, whichnot only lowers the process cost and simplifies the process steps, butalso shortens the process time, having a wide promotional value.

In the step (D), a plurality of second adhesive layers and a pluralityof graphene layers are sprayed alternatively on the graphene layerformed in the step (C). After each of the plurality of the secondadhesive layers and each of the plurality of the graphene layers issprayed, the each of the plurality of the second adhesive layers iscured under illumination. Finally, the graphene composite layer with adesired number of layers of graphene layers is obtained. Preferably, thenumber of layers of graphene layers in the graphene composite layer is1-30.

In the process described above, the graphene composite layer formed byalternatively spraying the second adhesive layer and the graphene layerhas high barrier property. Meanwhile, after each time the secondadhesive layer is sprayed, the second adhesive layer is cured underillumination, which not only improves the adhesive strength, but alsoshortens the process time. Furthermore, the preparation process ensuringthe same coating effect reduces the corona treatment used in the priorart, which not only lowers the process cost and simplifies the processsteps, but also shortens the process time, having a wide promotionalvalue.

Furthermore, the step (A) comprises following steps:

(A1) adding an initiator, a RAFT agent and a first reaction mixture to avessel containing DMF to form a second reaction mixture;

(A2) stirring the second reaction mixture until homogenous, andintroducing argon to a reaction system to remove oxygen therein;

(A3) heating and stirring the second reaction mixture to carry out areaction;

(A4) after a product with a desired molecular weight being produced, thereaction system being exposed to air and cooled rapidly in a cold waterbath to terminate the reaction;

(A5) purifying the product to obtain the hyperbranched cationicmussel-imitated polymer; and

(A6) formulating the hyperbranched cationic mussel-imitated polymer intothe aqueous solution of the light-curable adhesive having aconcentration of 0.5-5 mg/mL;

wherein the first reaction mixture comprises amulti-hydroxylbenzoylbenzamide ene amide monomer, a cationic monomer, aphoto-responsive monomer, poly(ethylene glycol) diolefine acid ester andpoly(ethylene glycol) olefine acid ester.

At first, the initiator, the RAFT agent, themulti-hydroxylbenzoylbenzamide ene amide monomer, the cationic monomer,the photo-responsive monomer, poly(ethylene glycol) diolefine acidester, and poly(ethylene glycol) olefine acid ester are added to a roundbottom flask containing DMF (i.e., N,N-dimethylformamide), and arestirred until homogenous. Preferably, the initiator has a concentrationof 0.012M. Next, argon is introduced to the reaction system to removeoxygen. Preferably, argon is introduced for 20-25 minutes. Then theround bottom flask is placed in an oil bath, and the mixture in theround bottom flask is heated and stirred, wherein the preferred oil bathtemperature is 60-90° C., and the preferred stirring speed is 600-800rmp. After the reaction is reached the expected conversion as well asthe product with the desired molecular weight is produced, the roundbottom flask is placed in the cold water bath to rapidly cool thereaction system. Later, the crude product is purified to obtain a lightbrown hyperbranched cationic mussel-imitated polymer. Preferably, thesolvent used for purification is dichloromethane and diethyl ether.After purification, the hyperbranched cationic mussel-imitated polymeris formulated into the aqueous solution of the light-curable adhesivehaving a concentration of 0.5-5 mg/mL.

Preferably, poly(ethylene glycol) diolefine acid ester is eitherpoly(ethylene glycol) diacrylate or poly(ethylene glycol)dimethacrylate, and can be used to adjust the esterification degree ofthe hyperbranched polymer. Poly(ethylene glycol) olefine acid ester iseither poly(ethylene glycol)methyl ether acrylate or poly(ethyleneglycol)methyl ether methacrylate, and can be used to adjust thesolubility of the hyperbranched polymer. Preferably, the molecularweight of the polyethylene glycol ranges from 200 to 6000.

Furthermore, the multi-hydroxylbenzoylbenzamide acylamide monomer has amolar percentage of 20-40%, the cationic monomer has a molar percentageof 30-40%, the photo-responsive monomer has a molar percentage of 1-5%,poly(ethylene glycol) olefine acid ester has a molar percentage of20-40%, and poly(ethylene glycol) diolefine acid ester has a molarpercentage of 5-10%.

Furthermore, in the step (A1), the initiator, the RAFT agent and thefirst reaction mixture are in a molar ratio of 1:2:100.

Furthermore, the initiator is 1,1-azobis(cyclohexanecarbonitrile),2,2′-azobis(2-methylpropionitrile) or 4,4′-azobis(4-cyanovaleric acid);and the RAFT agent is any one of2-(dodecyltrithiocarbonate)-2-methylpropionic acid,4-cyano-4-(phenylthioformylthio)pentanoic acid or2-cyano-2-propyl-4-cyanobenzene dithiocarbonate.

The present invention improves the existing preparation method of thereduced graphene oxide solution.

The step (B) of the method of preparing the film for the medicinepackaging specifically comprises the following steps:

(B1) adding graphite powder to concentrated sulfuric acid, stirringuntil homogenous in an ice water bath and then adding potassiumpermanganate, controlling a temperature of the ice water bath within arange of 10-15° C., and reacting for 2 hours;

(B2) transferring a reaction solution obtained in step (B1) to a waterbath to react at a constant temperature of 35° C. for 30 minutes,continually stirring the reaction solution and adding distilled water tothe reaction solution, and thereafter reacting at a temperature of 80°C. for 15 minutes;

(B3) adding a certain amount of 15 wt % hydrogen peroxide to thereaction solution until generation of bubbles, hot filtering thereaction solution, washing a filter cake with hydrochloric acid anddeionized water until a filtrate being neutral, and obtaining an aqueoussolution of graphene oxide;

(B4) diluting the aqueous solution of graphene oxide with deionizedwater, and ultrasonically treating the aqueous solution of grapheneoxide for 1 hour to obtain a graphene oxide solution having aconcentration of 0.1-5.0 mg/mL; and

(B5) mixing the prepared graphene oxide solution and a reducing agent ata mass ratio of 1:3, reacting at a room temperature for 2 minutes, anddiluting to obtain the reduced graphene oxide solution with a requiredconcentration.

The aforementioned technical solution improves the existing Hummersmethod for preparation of graphene oxide. On the one hand, the totalreaction time is less than 3 hours which is far less than that of theexisting Hummers method, and the steps such as standing step and dryingstep can be removed, effectively improving the production efficiency. Onthe other hand, the entire reaction process uses water as the solvent sothat the preparation conditions are environmentally friendly, and thepost-treatment process is simpler, lowering the production cost.

Compared with the prior art, the present invention has the followingadvantages and beneficial effects:

1. The light-curable adhesive prepared by the hyperbranched cationicmussel-imitated polymer significantly enhances the bonding strengthbetween the adhesive and the polymer film layer, as well as the bondingstrength between the adhesive and the graphene layers. The strongadhesion can be obtained with a less amount of adhesive so that thetotal thickness of the adhesive layers comprising the first adhesivelayer and the second adhesive layers is reduced, allowing the number oflayers of the graphene layers in the graphene composite layer toincrease greatly without the change in the total thickness and obviousincrease in the total mass, which not only meets the requirements of themedicine packaging material, but also obviously lowers the water vaportransmission and oxygen transmission, and significantly enhances thetensile strength.

2. The graphene composite layer of the present invention formed byalternatively spraying the second adhesive layer and the graphene layerhas high barrier property. Meanwhile, after each time the secondadhesive layer is sprayed, the second adhesive layer is cured underillumination, which not only improves the adhesive strength, but alsoshortens the process time. Furthermore, the preparation process ensuringthe same coating effect reduces the corona treatment used in the priorart, which not only lowers the process cost and simplifies the processsteps, but also shortens the process time, having a wide promotionalvalue.

3. The present invention improves the existing Hummers method forpreparation of graphene oxide. On the one hand, the total reaction timeis less than 3 hours which is far less than that of the existing Hummersmethod, and the steps such as standing step and drying step can beremoved, effectively improving the production efficiency. On the otherhand, the entire reaction process uses water as the solvent so that thepreparation conditions are environmentally friendly, and thepost-treatment process is simpler, lowering the production cost.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In order to make the objects, the technical solutions and the advantagesof the present invention clearer, the present invention is now furtherdescribed in details below with reference to the embodiments orexamples. The illustrative embodiments of the present invention and thedescription thereof are merely for purpose of illustration, and are notintended to limit the invention to the precise embodiments disclosed.

All the raw materials of the present invention are not particularlylimited in their sources, and are commercially available or can beprepared in accordance with the conventional methods known to thoseskilled in the art. For example, the photo-responsive monomer can besynthesized by the esterification reaction, and themulti-hydroxylbenzoylbenzamide acylamide monomer can be synthesizedaccording to the method disclosed in [J] Polymer Bulletin, 2012, 68,441-452, and in [J] Tetrahedron Letters, 2008, 49, 1336-1339.

All the raw materials of the present invention are not particularlylimited in their purity. The present invention preferably employs theanalytical purity or the conventional purity in the field of binderpreparation.

The expressions of the substitutes in the present invention are notparticularly limited, and use the expressions known to those skilled inthe art. Based on the common sense, those skilled in the art cancorrectly understand the meanings of expressions of the substitutes.

All the brands and abbreviations of all the raw materials of the presentinvention belong to the conventional brands and abbreviations in thefield. Each of the brands and abbreviations is clear in its relativefields. The raw materials may be purchased or prepared with theconventional methods by those skilled in the art according to theirbrands, abbreviations and corresponding use.

Example 1

Preparation of the Hyperbranched Cationic Mussel-Imitated Polymer P1:

N-(2-acrylamidoethyl)-3-(2,3,4-trihydroxybenzoyl)benzamide,N-(2-aminoethyl)methacrylamide hydrochloride,N-(2-acrylamidoethyl)-4-azido-2,3,5,6-tetrafluorobenzamide,poly(ethylene glycol)methyl ether acrylate (i.e. PEGMEA), poly(ethyleneglycol) diacrylate (i.e. PEGDEA) and the RAFT agent are added to asolution of N,N-dimethylformamide containing the initiator to form asecond reaction mixture, wherein the initiator is4,4′-azobis(4-cyanovaleric acid) and has a concentration of 0.012M. Thepolymerization of ethylene glycol in the PEGMEA is 15, and thepolymerization of ethylene glycol in the PEGDEA is 22.4,4′-azobis(4-cyanovaleric acid), the raft agent and the first reactionmixture formed by all the monomers involved in the polymerization are ina molar ratio of 1:2:100. The molar percentages ofN-(2-acrylamidoethyl)-3-(2,3,4-trihydroxybenzoyl)benzamide,N-(2-aminoethyl)methacrylamide hydrochloride,N-(2-acrylamidoethyl)-4-azido-2,3,5,6-tetrafluorobenzamide, PEGDEA andPEGMEA are respectively 40%, 30%, 5%, 15% and 10%. After the secondreaction mixture is stirred uniformly, the argon is introduced to thereaction system for 20-25 minutes to remove the oxygen. Then thereaction system is stirred at a stirring speed of 700 rmp and reacted ata temperature of 70° C. until an expected conversion is reached and aproduct with a desired molecular weight is obtained. Later, the reactionsystem is exposed to air and cooled in a cold water bath to terminatethe reaction. The product is further purified with dichloromethane anddiethyl ether to obtain a light brown hyperbranched cationicmussel-imitated polymer P1. Thereafter, the hyperbranched cationicmussel-imitated polymer P1 is dissolved in ethanol and water (volumeratio is 1:1) to obtain an aqueous solution of the light-curableadhesive S1 having a concentration of 15 wt %.

The structure of the hyperbranched cationic mussel-imitated polymer P1is as follows:

The detection result of the map for the structure of P1 is as follows:

¹H NMR (400 MHz, DMSO-D₆) δ (ppm) 7.90-8.2 (—NHCOC₆H₄CO—) 6.6-7.2(C₆H₂(OH)₃), 5.35 (—C₆H₃(OH)₂), 4.32 (CH₂OOC—), 3.50-3.8 (—CH₂CH₂O—,—OCNHCH₂CH₂—), 3.22 (CH₃O—), 3.03 (—OCNHCH₂CH₂NH₃Cl), 2.16 (—CH₂CHCO—),1.25-1.96 (—CH₂CHCO—);

¹⁹F NMR (188 MHz, DMSO-D₆) δ (ppm): δ −134.69˜−134.88 (2F),−147.58˜−147.71 (2F).

Example 2

Preparation of the Hyperbranched Cationic Mussel-Imitated Polymer P2:

N-(2-acrylamidoethyl)-4-(2,3,4-trihydroxybenzoyl)benzamide,N-(3-aminopropyl) acrylamide hydrochloride,N-(2-acrylamidoethyl)-4-azido-2,3,5,6-tetrafluorobenzamide,poly(ethylene glycol)methyl ether acrylate (i.e. PEGMEA), poly(ethyleneglycol) diacrylate (i.e. PEGDEA) and the RAFT agent are added to asolution of N,N-dimethylformamide containing the initiator to form asecond reaction mixture, wherein the initiator is2,2′-azobis(2-methylpropionitrile) and has a concentration of 0.012M.The polymerization of ethylene glycol in the PEGMEA is 45, and thepolymerization of ethylene glycol in the PEGDEA is 10.2,2′-azobis(2-methylpropionitrile), the raft agent and the firstreaction mixture formed by all the monomers involved in thepolymerization are in a molar ratio of 1:2:100. The molar percentages ofN-(2-acrylamidoethyl)-4-(2,3,4-trihydroxybenzoyl)benzamide,N-(3-aminopropyl) acrylamide hydrochloride,N-(2-acrylamidoethyl)-4-azido-2,3,5,6-tetrafluorobenzamide, PEGDEA andPEGMEA are respectively 20%, 33%, 2%, 35% and 10%. After the secondreaction mixture is stirred uniformly, the argon is introduced to thereaction system for 20-25 minutes to remove the oxygen. Then thereaction system is stirred at a stirring speed of 700 rmp and reacted ata temperature of 70° C. until an expected conversion is reached and aproduct with a desired molecular weight is obtained. Later, the reactionsystem is exposed to air and cooled in a cold water bath to terminatethe reaction. The product is further purified with dichloromethane anddiethyl ether to obtain a light brown hyperbranched cationicmussel-imitated polymer P2. Thereafter, the hyperbranched cationicmussel-imitated polymer P2 is dissolved in ethanol and water (volumeratio is 1:1) to obtain an aqueous solution of the light-curableadhesive S2 having a concentration of 15 wt %.

The structure of the hyperbranched cationic mussel-imitated polymer P2is as follows:

The detection result of the map for the structure of P2 is as follows:

¹H NMR (400 MHz, DMSO-D₆) δ (ppm) 7.90-8.2 (—NHCOC₆H₄O—) 6.6-7.2(C₆H₂(OH)₃), 5.35 (C₆H₂(OH)₃), 4.32 (CH₂OOC—), 3.50-3.8 (—CH₂CH₂O—,—OCNHCH₂CH₂—), 3.22 (CH₃O—), 3.03 (—OCNHCH₂CH₂NH₃Cl), 2.16 (—CH₂CHCO—),1.25-1.96 (—CH₂CHCO—);

¹⁹F NMR (188 MHz, DMSO-D₆) δ (ppm); −134.69˜−134.88 (2F),−147.58˜−147.71 (2F).

Example 3

Preparation of the Hyperbranched Cationic Mussel-Imitated Polymer P3:

N-(2-acrylamidoethyl)-4-(3,4-dihydroxybenzoyl)benzamide,N-(4-aminobutyl) acrylamide hydrochloride,N-(2-acrylamidoethyl)-4-azidobenzamide, poly(ethylene glycol)methylether acrylate (i.e. PEGMEA), poly(ethylene glycol) diacrylate (i.e.PEGDEA) and the RAFT agent are added to a solution ofN,N-dimethylformamide containing the initiator to form a second reactionmixture, wherein the RAFT agent is2-(dodecyltrithiocarbonate)-2-methylpropionic acid, and the initiator is2,2′-azobis(2-methylpropionitrile) and has a concentration of 0.012M.The polymerization of ethylene glycol in the PEGMEA is 5, and thepolymerization of ethylene glycol in the PEGDEA is 8.2,2′-azobis(2-methylpropionitrile), the raft agent and the firstreaction mixture formed by all the monomers involved in thepolymerization are in a molar ratio of 1:2:100. The molar percentages ofN-(2-acrylamidoethyl)-4-(3,4-dihydroxybenzoyl)benzamide,N-(4-aminobutyl) acrylamide hydrochloride,N-(2-acrylamidoethyl)-4-azidobenzamide, PEGDEA and PEGMEA arerespectively 25%, 35%, 5%, 30% and 5%. After the second reaction mixtureis stirred uniformly, the argon is introduced to the reaction system for20-25 minutes to remove the oxygen. Then the reaction system is stirredat a stirring speed of 700 rmp and reacted at a temperature of 70° C.until an expected conversion is reached and a product with a desiredmolecular weight is obtained. Later, the reaction system is exposed toair and cooled in a cold water bath to terminate the reaction. Theproduct is further purified with dichloromethane and diethyl ether toobtain a light brown hyperbranched cationic mussel-imitated polymer P3.Thereafter, the hyperbranched cationic mussel-imitated polymer P3 isdissolved in ethanol and water (volume ratio is 1:1) to obtain anaqueous solution of the light-curable adhesive S3 having a concentrationof 15 wt %.

The structure of the hyperbranched cationic mussel-imitated polymer P3is as follows:

The detection result of the map for the structure of P3 is as follows:

¹H NMR (400 MHz, DMSO-D₆) δ (ppm) 7.90-8.2 (—NHCOC₆H₄CO—) 6.6-7.5(N₃C₆H₄CO—, —C₆H₃(OH)₂), 5.35 (—C₆H₃(OH)₃), 4.32 (CH₂OOC—), 3.50-3.8(—CH₂CH₂O—, —OCNHCH₂CH₂—), 3.22 (CH₃O—), 3.03 (—OCNHCH₂CH₂NH₃Cl), 2.16(—CH₂CHCO—), 1.25-1.96 (—CH₂CHCO—).

Example 4

Preparation of the Films for Medicine Packaging M1, M2 and M3:

At first, the graphene oxide solution with a concentration of 15 mg/mLis prepared by the existing Hummers method. Thereafter, the preparedgraphene oxide solution and 98 wt % hydrazine hydrate solution are mixedat a mass ratio of 1:3, and reacted at the room temperature for 2minutes. Then the product is diluted to obtain the reduced grapheneoxide solutions with various concentrations for subsequent use.

Next, three PET films are cleaned and ultrasonically treated to removethe contaminants from the surfaces of the PET films.

The aqueous solutions of the light-curable adhesive S1 to S3 prepared inExamples 1-3 are respectively sprayed on the three PET films to form thefirst adhesive layer. Thereafter, the reduced graphene oxide solution issprayed on the first adhesive layer to form the graphene layer. Then thefirst adhesive layer is cured under a light condition, wherein the lightcondition is that the film is exposed at a distance of 25 cm under a1000 W medium pressure mercury lamp for 10 seconds.

Later the corresponding aqueous solutions of the light-curable adhesiveand the reduced graphene oxide solution are sprayed alternatively on thefilm. After each time the reduced graphene oxide solution is sprayed,the film is placed at a distance of 25 cm under a 1000 W medium pressuremercury lamp for 10 seconds to cure the second adhesive layer. Finally,films M1, M2 and M3 that each has 30 graphene layers are obtained.

Example 5

Comparative example 1 uses PVC sheet for packing solid medicine, andcomparative example 2 uses PVDC sheet for packing solid medicine.

The physical parameters of the films for medicine packaging M1, M2, M3,comparative example 1 and comparative example 2 of the same thicknessand mass are measured according to national standards, and the obtainedphysical parameters are shown in Table 1:

TABLE 1 physical parameters of the films for medicine packagingComparative Comparative Items Unit M1 M2 M3 example 1 example 2 WaterVapor g/m² · atm · day 0.32 0.38 0.39 1.01 0.42 Transmission Oxygencc/m² · atm · day 0.21 0.33 0.35 12.27 0.523 Transmission TensileStrength MPa 65.3/64.7 63.9/62.7 64.1/63.4 66.2/65.3 56.7/55.7(vertical/horizontal) Hear-sealing N/15 mm 10.9 11.1 10.8 11.5 10.8Strength Heavy Metals % <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 ReadilyOxidizable ml <1.5 <1.5 <1.5 <1.5 <2 Substance Nonvolatile Matter mg <25<30 <30 <30 <30 Total Bacterial unit/cm² <1000 <1000 <1000 <1000 <1000Count Total Mold Count unit/cm² <100 <100 <100 <100 <100 Colibacillusunit/cm² 0 0 0 0 0

Table 1 indicates that, with the same mass and thickness, compared withthe comparative example land comparative example 2, the films formedicine packaging prepared in Examples 1-3 have remarkably lower watervapor transmission and oxygen transmission, and effectively inhibitsmall molecules such as oxygen and water vapor from penetrating into thepackaging material, which avoids the oxidative deterioration of theactive ingredients in the drugs and inhibits the propagation ofmicroorganisims, thereby prolonging the shelf life of the drugs.

Example 6

On the basis of Example 4, the preparation method of the reducedgraphene oxide solution is improved.

1 g of graphite power is added to 23 ml of concentrated sulfuric acid.The reaction system is stirred until homogenous in an ice water bath.Then 2.5 g of potassium permanganate is added to the reaction system.The temperature of the water bath is controlled within a range of 10-15°C., and the reaction lasts for 2 hours. Thereafter, the reactionsolution of the reaction system is transferred to a water bath to reactat a constant temperature of 35° C. for 30 minutes. The reactionsolution is stirred during reaction. Next, 80 ml of distilled water isadded to the reaction solution, and the reaction last for 15 minutes ata temperature of 80° C. Then a certain amount of 15 wt % hydrogenperoxide is added to the reaction solution until generation of bubbles.The reaction solution is hot filtered, and the filter cake is washedwith hydrochloric acid and deionized water until the filtrate isneutral. An aqueous solution of graphene oxide is prepared forsubsequent use. Prior to using the aqueous solution of graphene oxide,the aqueous solution of graphene oxide is diluted with deionized waterand then ultrasonically treated for 1 hour to obtain a graphene oxidesolution having a concentration of 0.1-5 mg/mL.

Next, the prepared graphene oxide solution having a concentration of 5mg/mL and 98 wt % hydrazine hydrate solution are mixed at a mass ratioof 1:3, and reacted at the room temperature for 2 minutes. Then theproduct is diluted to obtain the reduced graphene oxide solutions withvarious concentrations.

In such technical solution, the total reaction time is less than 3 hourswhich is far less than that of the existing Hummers method, and thesteps such as standing step and drying step can be removed, effectivelyimproving the production efficiency. On the other hand, the entirereaction process uses water as the solvent so that the preparationconditions are environmentally friendly, and the post-treatment processis simpler, lowering the production cost.

The aforementioned embodiments and examples further illustrate thepurposes, technical solutions and beneficial effects of the presentinvention in detail. It is to be understood that the foregoing is onlythe embodiments of the present invention, and is not intended to limitthe scope of the present invention. Any modifications, equivalentsubstitutes, improvements and the like made within the spirit andprinciple of the present invention should all be included in the scopeof the present invention.

What is claimed is:
 1. A film for a medicine packaging, comprising apolymer film layer, wherein the polymer film layer is bonded with agraphene composite layer by a light-curable adhesive, the graphenecomposite layer comprises a plurality of graphene layers, and twoadjacent graphene layers of the plurality of the graphene layers arebonded by the light-curable adhesive; and the light-curable adhesivecomprises a hyperbranched cationic mussel-imitated polymer, and thehyperbranched cationic mussel-imitated polymer comprises amulti-hydroxylbenzoylbenzamide ene amide monomer, a cationic monomer,and a photo-responsive monomer.
 2. The film for the medicine packagingof claim 1, wherein the hyperbranched cationic mussel-imitated polymerhas a structure of formula (I):

wherein x is 1-10, y is 20-80, z is 30-80, w is 5-20, u is 20-80, K is1-5, n is 10-50, and m is 5-30; wherein R₁ is a chemical group having astructure of formula (II):

wherein R₃, R₄, R₅ or R₆ is individually selected from the groupconsisting of hydrogen and halogen; and wherein R₂ is a chemical groupselected from the group consisting of


3. The film for the medicine packaging of claim 2, wherein in formula(II), R₃, R₄, R₅ or R₆ is individually selected from the groupconsisting of hydrogen and fluorine; and R₁ is selected from the groupconsisting of


4. The film for the medicine packaging of claim 1, wherein a thicknessof the graphene composite layer is 10-200 nm.